Elizabeth "Beth" Roney (Sarah Wynter) is the main villainess from "An Unnatural Arrangement," episode 2.06 of Elementary (airdate October 31, 2013). She is an archaeologist who oversaw a dig in Afghanistan, with James Monroe and Sam Clennon as her partners. Further detail revealed that Beth was having an affair with Clennon, and when he was murdered, it was indicated that Beth's ex-husband, Cameron Hecht, killed him in a jealous rage.
It turned out that Cameron really did kill Clennon, but it was under the orders of Beth, who realized that the objects found at the digs were worth millions. After stealing the collectibles, the evil Beth sent Cameron to kill both Clennon and Monroe, all the while reconciling with Cameron and forming a partnership with him. Beth managed to cover her tracks by hiding one of the objects, after Sherlock noticed it out in the open when he and Watson first visited her home.
In the episode's climax, Sherlock and Watson returned with Detective Bell to arrest Beth, after they talked to Cameron. Sherlock stated that Cameron gave up Beth, and it was Beth's dog, Gotham, that gave both of them way. Beth stated earlier that Gotham barks at nearly any man who came near her home, but Cameron was the one exception. The villainous archaeologist was later handcuffed and arrested.